A hunchback appearance of the spine maybe a sign of Scheuermann's disease, a condition caused by an enlargement or deformity of the round back portion of the thoracic spine.

People with Scheuermann's disease have wedge-shaped vertebrae in their upper spine, which is caused by the front of the upper spine not developing as quickly as the back of the spine.

The wedge-shaped vertebrae cause the upper spine to arch downward.

Technically, Scheuermann's disease is not a disease at all but rather, a condition, or abnormality in the vertebrae.